Adding multiple administrators means you need to assign admin right to the selected users.
You can assign admin rights while creating new account for a user or later for the existing users.
To do this:
- Go to Account & Settings.
- Click Edit Users.
- Hover your mouse over the user you want to add as an administrator. Click the small blue icon that appears above the user.
- Below user details, check Administrator Account option.
- Click Save User.
- Repeat the above steps for all the users in order to create multiple administrator accounts.